A method is disclosed for synchronization, comprising obtaining baseband signal samples of a baseband information signal having an in-phase signal sample and a quadrature signal sample, the baseband information signal having been generated by mixing a received modulated carrier signal with a local oscillator (LO) signal having an LO frequency, the modulated carrier signal being an in-phase signal and quadrature signal having a substantially uncorrelated nature and derived from different input data sets; determining an offset frequency rotation based on an estimated residual correlation between the in-phase signal samples and the quadrature signal samples; and, deriving synchronization information from the offset frequency rotation, wherein the received modulated carrier signal is a quadrature-modulated signal with arbitrary orthogonal in-phase and quadrature signal components.

A distributed radio frequency communication system includes a remote radio unit (RRU and a baseband unit (BBU) and facilitates communication between a wireless terminal and a core network. The RRU receives a radio frequency signal from a wireless terminal and convert the radio frequency signal to digital baseband samples using receiver circuitry and an analog-to-digital converter. The RRU then adaptively compresses the digital baseband samples, using adaptive compression circuitry, to create fronthaul uplink information, and sends the fronthaul uplink information over a fronthaul link to the BBU using an adaptive fronthaul protocol. The RRU also receives fronthaul downlink information over a fronthaul link from the BBU using an adaptive fronthaul protocol and generates frequency-domain samples, based on the fronthaul downlink information received. It then creates time-domain baseband samples from the frequency-domain samples and converts the time-domain baseband samples into a radio frequency signal to send to the wireless terminal.

This application relates to a sideband suppression method performed at a computer device. The method includes: obtaining a target baseband signal, a target signal correlated parameter corresponding to the target baseband signal, the target signal correlated parameter including at least one of a signal feature parameter corresponding to the target baseband signal or a signal feature parameter of a carrier signal corresponding to the target baseband signal, and a corresponding target sideband suppression parameter according to the target signal correlated parameter; performing signal correction on the target baseband signal based on the target sideband suppression parameter, to obtain a target corrected baseband signal, the target sideband suppression parameter being used for suppressing a power of a first suppression sideband corresponding to the target baseband signal; and inputting the target corrected baseband signal to a modulator for signal modulation, to obtain a target modulation signal corresponding to the target baseband signal.

A robust frequency drift tracking receiver. The received signal is translated to an intermediate frequency in the RF stage by a quadrature demodulator, and is then brought into the base band by a digital mixer made by a CORDIC. A base band processing stage allows for a synchronization of the receiver relative to the data frame, to estimate data and to output a counter-reaction signal to the CORDIC, obtained by integration of successive frequency corrections, with a predetermined step.

A distributed radio frequency communication system facilitates communication between a wireless terminal and a core network. The system includes a remote radio unit (RRU) coupled to at least one antenna to communicate with the wireless terminal. The RRU includes electronic circuitry to perform at least a first portion of a first-level protocol of a radio access network (RAN) for communicating between the wireless terminal and the core network. The system also includes a baseband unit (BBU) coupled to the core network, and configured to perform at least a second-level protocol of the RAN. A fronthaul link is coupled to the BBU and the RRU. The fronthaul link utilizes an adaptive fronthaul protocol for communication between the BBU and the RRU. The adaptive fronthaul protocol has provisions for adapting to conditions of the fronthaul link and radio network by changing the way data is communicated over the fronthaul link.

An apparatus for estimating carrier frequency offset includes a notch frequency setting circuit, N notch filters, an M.sup.th power circuit, a spectrum generating circuit, a peak frequency determining circuit, a comparing circuit, and a frequency offset determining circuit. The notch frequency setting circuit sets different notch-frequencies for the notch filters, which generate N filtered signals by filtering an input signal. The M.sup.th power circuit performs an M.sup.th power calculation on the N filtered signals to generate N M.sup.th power filtered signals. The spectrum generating circuit generates N M.sup.th order spectra for the N M.sup.th power filtered signals. The peak frequency determining circuit determines respective peak frequencies of the N M.sup.th order spectra. The comparing circuit identifies an optimal peak frequency from the N peak frequencies. The frequency offset determining circuit determines an estimated carrier frequency offset according to the optimal peak frequency.

A method comprising generating a baseband information signal by mixing a received modulated carrier signal with a local oscillator (LO) signal having an LO frequency; obtaining baseband signal samples of the baseband information signal having a baseband signal magnitude and a baseband signal phase; determining a cumulative phase measurement associated with baseband signal samples having a baseband signal magnitude greater than a threshold; and, applying a correction signal to compensate for an LO frequency offset of the LO frequency based on the cumulative phase.

Embodiments of a station (STA) and method for communication in accordance with phase noise compensation are generally described herein. The STA may determine, based at least partly on one or more operational parameters, whether to perform phase noise compensation of data symbols of a received protocol data unit (PDU). For instance, the STA may compare the operational parameters with one or more thresholds. The STA may further determine a method of phase noise compensation based at least partly on one or more operational parameters. As an example, the STA may determine a type of interpolation to be used for an interpolation of phase noise estimates of pilot symbols to determine phase noise estimates of data symbols. Example operational parameters may include a signal quality metric, a carrier frequency offset (CFO) measurement and/or modulation and coding scheme (MCS).

An apparatus for estimating carrier frequency offset includes a notch frequency setting circuit, N notch filters, an M.sup.th power circuit, a spectrum generating circuit, a peak frequency determining circuit, a comparing circuit, and a frequency offset determining circuit. The notch frequency setting circuit sets different notch-frequencies for the notch filters, which generate N filtered signals by filtering an input signal. The M.sup.th power circuit performs an M.sup.th power calculation on the N filtered signals to generate N M.sup.th power filtered signals. The spectrum generating circuit generates N M.sup.th order spectra for the N M.sup.th power filtered signals. The peak frequency determining circuit determines respective peak frequencies of the N M.sup.th order spectra. The comparing circuit identifies an optimal peak frequency from the N peak frequencies. The frequency offset determining circuit determines an estimated carrier frequency offset according to the optimal peak frequency.

A digital broadcast receiving system includes a known data detector, a carrier recovery unit, and a timing recovery unit. The known data detector may detect known data information inserted and transmitted from a digital broadcast transmitting system and using the known data information to estimate initial frequency offset. The carrier recovery unit may obtain initial synchronization by using the initial frequency offset, and may detect frequency offset from the received data by using the known sequence position indicator so as to perform carrier recovery. The timing recovery unit may detect timing error information from the received signal by using the known sequence position indicator so as to perform timing recovery.